Distribution and habitat use of a rare native crayfish: Implications for conserving Data Deficient species

Abstract

Few observations exist for the Kisatchie painted crayfish (Faxonius maletae), and little is known about its distribution, habitat use, or population structure. The lack of basic ecological data has led to a ‘Data Deficient’ designation, a category of conservation concern that is often overlooked for management actions. This work provides updated data and practical management suggestions for similarly Data Deficient species. Comprehensive (i.e. beyond known collection sites) crayfish surveys paired with habitat assessments across north‐east Texas were conducted. Among 74 survey sites in 10 counties within and adjacent to the known range for F. maletae, eight total crayfish species were encountered within 35 of these sites (47.3% of the total). Thirteen F. maletae individuals were collected across seven sites (9.5%). Notably, two individuals were found where the species had not been previously observed. Stepwise multiple logistic regression indicated that conductivity and availability of exposed root masses were positively related to F. maletae presence, although neither factor was statistically significant on its own. Neither nonmetric multidimensional scaling nor canonical correspondence analysis identified patterns between F. maletae presence and the presence of other crayfish species. Overall, F. maletae is geographically rare and occurs in exceptionally low abundance, challenging the ability to understand drivers of its distribution. However, given the depth of this survey, we can confidently say that F. maletae is no longer Data Deficient; rather, there is compelling evidence that it has a limited range and small population size. The Data Deficient versus rarity debate has wide‐reaching impacts on the conservation of aquatic taxa; species that are Data Deficient require heightened research focus in general, whereas rare organisms require targeted management to protect specific habitats. Furthermore, we suggest that future management efforts should focus on maintaining current populations through active monitoring to inform the potential habitat suitability of new areas for protection.

Activity, movement and habitat‐use patterns of a critically endangered endemic Australian freshwater crayfish

“…Native populations of freshwater crayfish are under threat from numerous stressors, including habitat modification and degradation, invasive species and disease, and at least one‐third of all species are considered at risk of extinction (Richman et al., 2015). The conservation of threatened crayfish populations is often underpinned by knowledge of their habitat requirements (Hays et al., 2023; Smith et al., 1996; Vezza et al., 2016) and movement patterns (Florko et al., 2021). While there has been a sizeable amount of research into the habitat‐use and movement patterns of some species of freshwater crayfish (e.g., Anastácio et al., 2015; Danêk et al., 2018; Robinson et al., 2000; Ryan et al., 2008), it is apparent that there is a high degree of variation in these patterns between species.…”